Anne-Marie Houle

What volume can a child normally store in the bladder at a safe pressure

To determine what volume a child can normally store in the bladder at a safe pressure 923 pediatric urodynamic studies were reviewed, and 69 examinations done on 17 boys and 52 girls were considered normal. Patient ages were recorded and body surface areas were calculated. A continuous intermediate flow water cystometrogram had been performed. Total bladder capacity in milliliters, full resting pressures (cm. water), and the volumes (milliliters) and percentages of the total bladder capacity stored at detrusor pressures of less than 10, 20, 30 and 35 cm. water were measured. We found that 98.1% of the total bladder capacity could be stored at a detrusor pressure of less than 20 cm. water in more than 95% of the children independently of age or body surface area and 99.9% could be stored at a detrusor pressure of less than 30 cm. water. An approximation of the minimal acceptable total bladder capacity for age can be calculated by 16(age) + 70 in ml. According to our results, we proposed criteria for good storage characteristics of the bladder in children.

Extravesical Nondismembered Ureteroplasty with Detrusorrhaphy: A Renewed Technique to Correct Vesicoureteral Reflux in Children

We performed an extravesical nondismembered reimplant to correct surgically primary vesicoureteral reflux in 45 patients (65 renal units) between April 1989 and September 1990. Of the units 6 had grade I reflux, 16 grade II, 23 grade III, 14 grade IV and 6 grade V. Only patients with primary reflux were included in this study. The success rate was 100% for grades I to III, 92.9% for grade IV and 66.7% for grade V. Overall, the reflux was cured in 62 of the 65 operated renal units (95.4%) or 95.6% of the patients (43 of 45). Postoperative morbidity and complications were minimal. No cases of postoperative obstruction were detected on excretory urography 6 weeks postoperatively. Seven children (16%) suffered from transient inadequate bladder emptying as assessed by post-void ultrasound residual evaluations. This problem resolved spontaneously after a maximum of 4 weeks of clean intermittent catheterization. Compared to conventional transvesical technique, the discomfort related to bladder spasms during the postoperative period was subjectively decreased and patients had no prolonged hematuria.

BLADDER FUNCTION BEFORE AND AFTER SELECTIVE DORSAL RHIZOTOMY IN CHILDREN WITH CEREBRAL PALSY

PURPOSE Approximately a third of children with cerebral palsy are expected to present with dysfunctional voiding symptoms. Selective dorsal rhizotomy, which is indicated for managing lower extremity spasticity in children with cerebral palsy, also has the potential of affecting bladder function. We evaluate the impact of selective dorsal rhizotomy on bladder function by comparing preoperative and postoperative symptoms, and urodynamic parameters in children undergoing selective dorsal rhizotomy for spasticity. MATERIALS AND METHODS We reviewed urodynamic studies in 25 boys and 15 girls with a mean age plus or minus standard deviation of 5.43+/-2.1 years who underwent selective dorsal rhizotomy for spasticity at our institution between January 1992 and September 1995. Urodynamics were performed preoperatively only in 22 patients, preoperative and postoperatively in 13, and postoperatively only in 5. Preoperative urodynamic studies were done within 2 weeks of surgery and postoperative studies were done at least 6 months after surgery (mean 1.32+/-0.65 years). RESULTS Of the 35 patients with preoperative urodynamic studies total bladder capacity, pressure specific volumes and full resting pressure were abnormal for age in 23 (65.7%). In addition, 17 of the 23 children (74%) were completely asymptomatic. In the group that underwent preoperative and postoperative urodynamic studies there was significant improvement in total bladder capacity (p <0.005) and pressure specific volumes (p <0.005) using the paired Student t test. All children had neurological improvement postoperatively, 5 of 7 (71%) who were incontinent preoperatively became continent and none had deterioration on urodynamics. CONCLUSIONS At least half of the children with spastic cerebral palsy have clinically silent bladder dysfunction. Selective dorsal rhizotomy improves spasticity and significantly improves bladder storage characteristics. We propose that urodynamic studies be included in the evaluation of children with spastic cerebral palsy who are possible candidates for selective dorsal rhizotomy to treat lower limb spasticity.

A new technique for dynamic analysis of bladder compliance

We propose an alternative method of measuring compliance that takes into account the multiple phases of bladder filling. We describe our new technique, dynamic compliance analysis, and evaluate its clinical applicability. To perform the analysis we digitized a cystometrogram curve at a sampling rate of 2 samples per second using an MS-DOS computer system. A program designed to retrieve the stored data was used to analyze the subtracted bladder pressure. The result yielded a value of compliance every half second that was then plotted on an x-y graph, with instantaneous compliance as the dependent variable and per cent of total volume infused as the independent variable. To determine the clinical applicability of this technique we chose 63 curves from clinically normal patients. The results of the dynamic compliance analyses were predictable. The dynamic compliance values for the normal group had a minimum that was always greater than 10 ml./cm. water throughout the tonus limb (phase 2) of the cystometrogram. We conclude that dynamic compliance analysis yields more information about bladder response during filling, similar to the stress-strain curve used in the study of solid mechanics.

Magnetic resonance imaging in children with voiding dysfunction : Is it indicated?

PURPOSE We evaluated the role of magnetic resonance imaging (MRI) of the lumbosacral spinal cord in children with complicated voiding dysfunction and normal neuro-orthopedic examination. MATERIALS AND METHODS We reviewed the records of 32 consecutive children with complicated enuresis who were referred for neurosurgical evaluation, including those with a history of refractory voiding dysfunction or incontinence associated with persistent vesicoureteral reflux, encopresis, or associated leg or back pain. Nine patients were excluded from study because of urethral or anorectal anomalies, or failure to meet the inclusion criteria. Eligible for study inclusion were 23 children with a mean age of 8.9 years. Complete neurological and orthopedic examinations were normal in all patients except 1 with mild scoliosis and 1 with congenital facial palsy. RESULTS Urodynamic studies revealed instability in 14 cases, hypertonia in 7, hyporeflexia in 2 and detrusor-sphincter dyssynergia in 4. Skeletal abnormalities, mostly spina bifida occulta, were detected in 16 of the 23 children (70%). Spinal MRI was normal in 21 patients (91.3%), including 1 with a tethered cord and lipoma associated with a complex skeletal abnormality, and 1 with a nonprogressive, nonsurgical T7 to T9 syrinx. Only the case of lipoma required neurosurgical intervention. CONCLUSIONS The value of MRI is limited in children with voiding dysfunction and a normal neuro-orthopedic assessment. This study should be reserved for patients with associated neuroorthopedic findings or complex skeletal deformity on plain x-ray.

Hydronephrosis with diffuse or segmental cortical thinning: impact on renal function.

PURPOSE Management of hydronephrosis has changed considerably with the routine use of prenatal ultrasonography. Increased dependence is now placed on nuclear renographic differential renal function, and many urologists consider surgical intervention for ureteropelvic junction obstruction with significant decrease in renal function (less than 40%). Correlation between differential renal function and the degree of dilatation diagnosed by ultrasound has not been reported. In addition, no difference between hydronephrosis associated with either diffuse or segmental cortical thinning has been made, as both are classified as grade IV according to the Society of Fetal Urology classification. Based on clinical observation we hypothesized that hydronephrotic grade IV kidneys with diffuse parenchymal thinning are associated with worse renal function and are distinct from those with segmental cortical thinning. MATERIALS AND METHODS We performed a retrospective study of patients who underwent pyeloplasty between January 1996 and December 1998. Hydronephrosis was graded according to Society for Fetal Urology classification and all diuretic renograms were performed in a standardized fashion. Grade IV kidneys were divided into IVA (segmental cortical thinning) and IVB (diffuse cortical thinning). Statistical correlation of grade and differential renal function was performed using a chi-square test. RESULTS Images were available for review in 77 patients. Average patient age at intervention was 20.4 months and 7.6 years of the prenatally and postnatally detected hydronephrosis groups, respectively. Of the 77 cases 25 had grade IVA and 18 had grade IVB hydronephrosis. Of the grade IVB hydronephrosis cases 66% had less than 40% differential renal function compared to 24% in group IVA (p <0.05). CONCLUSIONS Patients with grade IVB hydronephrosis secondary to ureteropelvic junction obstruction have a higher risk of significant decrease in renal function. Group IVA has significantly better function than group IVB and characteristics similar to grade III hydronephrosis cases. Grade IVB hydronephrosis should monitorized closely as earlier intervention may be warranted to avoid progressive deterioration of renal function.

LONG-TERM RESULTS OF PERCUTANEOUS ENDOPYELOTOMY IN THE TREATMENT OF CHILDREN WITH FAILED OPEN PYELOPLASTY

PURPOSE We reviewed our experience with the safety and long-term efficacy of percutaneous endopyelotomy in children with secondary ureteropelvic junction obstruction who previously underwent open pyeloplasty. MATERIALS AND METHODS Nine patients a median of 7 years old underwent endopyelotomy between June 1985 and July 1995. Anderson-Hynes pyeloplasty had previously been performed in all children. Antegrade endopyelotomy was done with a cold knife in conjunction with balloon dilation in some cases. Postoperative stenting lasted 6 weeks. RESULTS The median interval between pyeloplasty and endopyelotomy was 7.5 months. Mean operative time was 240 minutes. Percutaneous endopyelotomy was successful in 8 of the 9 patients. One patient who required repeat endopyelotomy after 4 years is presently well at 5 years of followup. Average followup was 5.6 years (range 2 to 10). There was a low morbidity rate, including 1 case of urinary tract infection, 1 of pneumonia and 1 that required blood transfusion. CONCLUSIONS Percutaneous antegrade endopyelotomy is a safe, effective and durable alternative for children who previously underwent unsuccessful pyeloplasty.

Prenatal vesico‐allantoic cyst outcome – a spectrum from patent urachus to bladder exstrophy

The purpose of this study is to assess the prognostic significance of a cystic vesico‐allantoic communication discovered on prenatal ultrasound in terms of its effect on the developing urinary tract.

True Hermaphrodites: An Experimental Model in the Mouse

When the Y chromosome from the Mus musculus domesticus mouse strain is placed onto the C57BL/6J mouse background ovarian and testicular components develop in half of the XY progeny (B6.YDOM), providing an excellent model of true hermaphroditism. We examined the correlation between gonadal sex and development of the internal genital tract in the B6.YDOM mouse at puberty. Of 55 mice examined 20 had bilateral testes, 33 were true hermaphrodites and 2 had mixed gonadal dysgenesis. In all mice with bilateral testes male accessory sexual organs developed bilaterally. In the true hermaphrodites testes were found on either side but preferentially on the left side. When a male feature was present on the ipsilateral side of the ovary, the seminal vesicle was more frequently found than prostate or vas. Testicular mass was significantly different between the true hermaphrodites with and those without bilateral seminal vesicles. Similar difference was found in those with and without bilateral prostates. The serum testosterone level was not significantly different between these groups. We conclude that the testicular mass is a better discriminant than serum testosterone for the presence or absence of seminal vesicles and prostates at puberty.